Tube-drawing plug



Patented @et 7, i924.

Unirse sr 'rss 1,51 Midi PATENT FFECE.

TUBE-DRAWING- PLUG'.

Application filed March 26, 1923.

T 0 al! whom t may concern:

Be it known that I, JOHN H. OROURKE, a citizen of the United States, residing at ldfvaterbury, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Tube- Drawing Plugs, of which the following is a specification.

My said invention relates to a plug for tube drawing machines, and it is an object thereof to provide a plug which shall have all the desirable characteristics of those now in use while at the same time it will provide for greater economy in time, labor and material.

Referring to the accompanying drawings, which are Vmade a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a side elevation of the device in use, the die and tube being shown in section,

Figure 2 an elevation of the plug on an enlarged scale, and

Figure 8 an elevation of a plug of the typo hitherto employed for this purpose.

ln the drawings reference character 10 indicates a die which contacts with the eX- terior surface of a tube which is to he reduced in diameter and extended in length in the well-known operation of tube draw ing. A plug 11 is adapted to be positioned on a rod 12, the latter being so mounted as to be capable of retraction from the die. Usually the rod is pivoted at its rear end so that it can be swung upward from the die for removal or replacement of the plug. At the end of the rod is a nut 18 here shown as separated from the plug by a washer 14 and serving to hold the plug in place against a shoulder on the rod formed by reducing the outer end of the same, as indicated in dotted lines in Figure 2.

The plug 11 tapers regularly from the middle toward each end as shown with a taper of about siXteen thousandths to the inch. It is adapted to be inserted within the die, the precise position being determined by an adjustment at the rear end of the draw-bench extension (not shown). In the use of the device the tube 15 is drawn between the die and the plug, the latter being set so as to determine the inner diameter of the tube and the thickness of its wall. Tubes such as 15 are successively placed over the plug and drawn by the usual means until Serial No. 627,897.

the surface of the plug at the point of contact becomes worn 'sufficiently to interfere with proper' operation of the device when the plug, if of the old type shown in Figure 3, must be discarded so far as drawing tubes of the specified size is concerned though it can still be utilized for drawing larger or smaller tubes according to the distance be tween the worn part and the respective ends of the plug. It may still be ground down to a smaller size. My improved plug can be re-ground on the same principles as illustrated in Figures 1 and 2, so that it still has two wearing surfaces instead of one as on a plug of the former type. A new plug is then placed on the rod and the parts are rel-set to bring the same to the correct position relative to the die.

With my device all that is necessary is to reverse the plug on the rod and bring the parts to the same position as before, the two tapering ends being exact duplicates of each other thus doing away with any need of resetting. The rod is secured at its pivoted end (not shown) in such a manner that it can be moved bodily with the plug to adjust the same relative to the opening in the die, this being to compensate for wear on the inner surface of the die in. addition to the advantage of being able to reverse the plug without ref-setting of parts.

In the use of the plug tubes will be drawn on it until an annular depression is formed in the` plug, when a plug of the old type must be replaced with another while mine is merely reversed, and used until a similar groove is worn at the other end. The old plug may be set to draw tubes of different sizes, say at live different points of the part 16 upv to about the dotted line located midway of the length of the plug. It is never set so as to use the surface on the part 16', as the plug loses its balance and chat-v ters in a manner to interfere with the work, By making the plug slightly longer, with about the proportions shown in the draw ings I am able to set it to draw at from four to live points at each end of the plug, which is in balance regardless of which end is forward. Furthermore said positions for the two ends are duplicates of each other, so that a plug can be used twice as long on tubes of the same size, thus saving time on the job, and cutting do-wn the number of plugs needed in the mill.

It is to be noted not only that the same plug may be used twice as long as ak plug of the old type, but that` twice as inany tubes may be drawn With it as With thel plugs now used, these conditionsy resulting 111 savf ing ot time and labor both in making plugs, in handling and transporting them and in drawing tubes. In addition to this the saving of material is an important advantage, the material from which they are marde. being high priced 'tool steel and each double plug requiring very little more steel than the old single plugs, the new' plugs being a little `longer and. being thicker at the middle.

l{a1/*ing thus fully described my said invention, what l claim as new and desire to secure by Letters Patent, is: i

l.A ln a tube drawing machine., a die, a rod arranged to be positioned cio-axially with the die or to be retracted therefrom and a reversible plug removably mounted on the rod said plug having oppositely din rected truste-conical surfaces ladapted to be selectively positioned concentrically with the die, substantially as set forth. V

2. In a tube-drawing machine having ak longitudinally adjustable rod arranged to hold a plug in ixed position relative to a ydie dur-.ing the vdrawing operation7 the combination of a reversible plug tapering from the middle ton/'ard each end, and means to secure the saine removably on the rod, subsrta-ntially asv set forth.

In Witness whereof, I have hereunto vset my hand and seal iat Waterbury, Conneeti- '35 cut, this sixteenth day ot March, A. D. 

